The present disclosure relates to a semiconductor device and, for example, relates to a semiconductor device including a CPU core and a plurality of peripheral circuits used for the CPU core.
Vehicle-mounted control systems are required to be built with functional safety design in each single part today. Particularly, vehicle control MCUs (Micro Controller Units) are required to improve their failure self diagnosis functions. An example of failure self diagnosis functions is a function of detecting whether a failure such as CMOS breakdown is occurring by making a DFT (Design For Test) circuit operate in a single semiconductor device (Field-BIST: DFT circuit that can be used in client environments). Another example of failure self diagnosis functions is disclosed in Japanese Unexamined Patent Application Publications Nos. H9-325946 and 2014-132384.
The microprocessor disclosed in Japanese Unexamined Patent Application Publication No. H9-325946 supplies the same test pattern generated in a test pattern generation circuit to a plurality of microprocessors at the same time, compares and determines, by a comparator circuit, whether test results obtained in those microprocessors are all the same or not, and, when they are all the same, determines that all of the microprocessors are operating normally.
The microcomputer disclosed in Japanese Unexamined Patent Application Publication No. 2014-132384 includes an output comparison unit that compares outputs of a main core and a checker core in a normal operation mode, a shift result comparison unit that compares outputs of scan chains of the main core and the checker core in a mismatch location specification mode, a table storage unit that stores a table containing information about a plurality of flip-flops and a plurality of functional blocks, and a control unit that switches the mode to the mismatch location specification mode when a mismatch is detected by the output comparison unit in the normal operation mode, and extracts, from the table, the functional block corresponding to the flip-flop specified based on a comparison result of the shift result comparison unit and stops the function of the functional block in the mismatch location specification mode.